In a conventional display, it is common that a contrast of a displayed video or a light emission luminance of a backlight is adjusted by a manual operation of an user. In recent years, a method of dynamically controlling a contrast of a displayed video and a light emission luminance of a backlight in accordance with an input video signal varying with the lapse of time has been proposed in order to improve image quality or reduce consumption power (see, for example, Patent Document 1). In accordance with the above method, reduction of consumption power can be achieved while raising a contrast of a displayed video.